Go Down

Topic: How does this circuit look for PWM'ing 40 RGB LED's? (Read 1 time) previous topic - next topic


I am putting together a house lighting project using RGB's, my plan is to use a TLC5940 driving 5 RGB LEDS (15 PWM's), and multiplexing 8 LED's onto each channel, giving 40 total RGB LED's with this setup.  I would like anyone with much better expertise then my own as to if the circuit I designed is adequate enough.  I did breadboard the design with 4 multiplexed LED's per channel and it seemed to run fine (though I will probably have to use dot correction for best results...).  Note that the schematic is not complete, I did not bother at this point to fully schematic out the 595 and 5940's power, ground, and arduino connections, but the schematic for the LED's is there.  I am biasing the 5940 for 40ma per channel considering how fast the multiplexing is happening to get a good brightness (I could go to 60ma but I will be taxing my available power supplies doing so).

I am not sure either about the best placement of capacitors for power smoothing, as I noticed with the scope that the switching or PWM is not as clean as it should be, so any ideas on that would be great too, thanks!



Oct 09, 2012, 11:14 am Last Edit: Oct 10, 2012, 08:12 pm by MatCat Reason: 1
Here is a video demonstrating my circuit, been running for about an hour now and all components involved are as cool as when I pulled them from the parts drawer, so I think it works however any ideas are still welcomed!



Wow 51 views and not a single reply!

Got to tell you something about your previous behavoure then.

Excuse me?

Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131